Electron superhalogens as positronium superhalogens.

Area of Science:

• * Theoretical chemistry
• * Quantum mechanics
• * Atomic and molecular physics

Background:

• * Positronium (Ps) forms stable complexes with atoms and molecules.
• * Fluorine (F) exhibits the highest reported Ps binding energy (2.95 eV).
• * Superhalogens possess electron affinities greater than chlorine (Cl).

Purpose of the Study:

• * Define and identify Ps-superhalogens: molecules with Ps binding energies exceeding that of F.
• * Investigate positronium and positron binding to neutral and anionic superhalogen molecules (MXk).
• * Analyze the factors influencing positron affinity in these systems.

Main Methods:

• * Employed multicomponent MP2 calculations for positron systems.
• * Studied MXk superhalogens (M = Li, Na, Be, Mg, B, Al, Si, P; X = F, Cl, Br).
• * Evaluated binding energies and stability against dissociation channels.

Main Results:

• * Identified six MFk systems as Ps-superhalogens with Ps binding energy > 2.95 eV.
• * Aluminum tetrafluoride (AlF4) achieved a record Ps binding energy of 4.36 eV.
• * Electrostatic interactions predominantly determine positron affinity; relaxation effects are negligible.

Conclusions:

• * Predicted the energetic stability of 22 out of 24 PsMXk complexes.
• * Established AlF4 as a new record holder for Ps binding energy in neutral molecules.
• * Confirmed the viability of Ps-superhalogens for advanced chemical studies.